Synchromesh change-speed gearing



Jan. 24, 1950 FROST 2,495,411

' SYNCHROMESH CHANGE-SPEED GEARING Filed Sept. 7, 1945 2 Shee'ts-Sheet 1 fnvenZZr [3 90] i 130.92

Jan. 24, 1950 v r E. D. FROST SYNCHROMESH CHANCE-SPEED GEAR-INC Filed Sept; 7, 1945 Patented Jan. 24, 1950 Edganhavidlircat,(icventrnfinalamh-asskm tmfiumbar L mitcdb Stoka, Gmentrxa. ngland! Anpliication Stpt'ember 7 1945; SegijaF No. 614,842 In- Great Britain Sentembew 1 6,, 1944 tClaims, (Cl. 15%53 Thisinvention relatesrto synchromesh changeaspeed: gearing, of thekindghaving: a dOHbIBpfi-fitt? ing; slidable; positive clutch. element, in; thafhnm. of'acollar,which hasitoipass a maskin or baulkr' ing ring? (in; whichever direction it: is move-dz) to.-

mesh, when. synchronism: is. reached, with. the (507 acting positive clutch element; theappropriate bauIking ring having a frictional: surface which. is forced axially.- into frictional engagement with. a firi-cti'onal siu face of? theassociated positiva clutch element; to-producesynchronism, by' axial? movement; of the collar, the baullcingrings hav ing a driving; engagement, providing slight: arr-..= gul'a-n clearance, with a hub member upon which thecollarisnon-rotatably mounted and; which isaxially-fast:

Usually in sucha synchro-mesh d'evice each; baulk-ing ring has external teeth, between which the teethon the collar-canpass; when synchroni's mhas been reached;- and each baulking ring isformed with a female cone surface adapted friction-ally to engage a male cone surface; (the I two male cone; surfaces being fast either with a. driving shaft and" adriven gear, respectively; as, is illustrated in the accompanying dlfawing s o 1t with two driven gears, respectively) withwhich the saidhubmember is ohe. n r-meshed by. the: collar.

w ar. of. the frictional. surfaces takes. place. ns sf ry op rationtends o result... Qnaoi. my obje ts ist provide a very d fini e. frictiona pr ure withwhichsynchrqnism. will; besp eded; up, resulting inv l'ess Wear occurring at the histionaijsurfaces, whereby thelif'e of the device-will be; increased... Another object is to facilitate pro,- duction of the device, andto. distribute therljoad through which the frictional engagement takes,

place. at a. large number of points. Another ob ject is to ensure. that there shall. be: no frictional. dragbetweenthe pairs offrictional surface ,when not engaged. ineffecting synchronism.

According. to. the; inventioneach, of the baulle ing rings is, tied. at a. number, of points (so thatthere wi l be substantially no, clearance: r. lost motion in an axial; direction) to, an; outwardly. springing ring adapted to engage, aninternal pe ripheral, groove in the-collar, the spring; ringserving, on, the, initial movement of the; collar either axial direction, for. forcing the; selected? ulkina ing; atv each. of. the; tying mints inta frictional! enaagamantwith: the frictional: 5 Jane Qfi he assoc ated. nasitiva clutch; element; whiia ma athon-banking; being; 1; 1y; ith

drawn. still! further. from. its enacting irictimala urface. 'Ehara may; for example be six angularlil-spacedx tying points;

Thus; inacarryingzout the:intention,v each bauik n 1:i.ng;,in. the form of: afemale cone witnexternali radiakmaskiha teeth to coas with; the; teeth of the slidable; coliar.;. may be formed with; six:

circumixirmtiallyspaced, 1atena1 yextendin arms. tha off: which arefQr-ked; in; a radial tozi izn lupmtid n' external annular anima e racemes. the. spring lunar preferably with subsiamtiaiin no laterals clearance (11 e}. in, an. axial diizcctiam of the; ring) ut. naturallys he f mka: provide radial; clearance to.- al-lowof, the rin na nardennesseaintothe roove of. theiorie limbs:

: when... tha cQHan-r is: moyed axially through. the

teeth; Qff ither bau-lkina r ng; The.- lateral arm IQmi the: two. haulki-ng: rings are preferably aneurysm ogether pairs in slots,, in the hub,-

memben, which provide the angular clearance.- above-mentioned, and the spring; ring has thenecessary working: clearancein the: hub 1 member.

In. the; ac omp yin drawings Eig ira I. isia. longitudinal; section, through oneflm 0i? ammo-mesh device,- according; to the inl ventihn algem mainly on theline, l.-l QfjFigure;

FiEIliPQEZI S:@,OIEQSS,-SB.G1 i I1 thereof taken onthe .1 Scale, owiespqndingatovEiguneL,of the upp rpon Qni Qfi the; deyicm but. tha section in this; case; is tahcm mainliy on: theiina 474: of; Figure 2; Qn-Fig-- wait The drawings show a drivenshatt [2; with a ear fastrthereqm and. drivi fi r: H1 Itotative- 1y; m mma hrough; a. bearing; I=5= on: a. reduced DOM-i931 thereon. Between the..- two; gears l3. and: t4; hank-1am haaa.serrateri:portionw lfi=up0n which is; fiil d at member l1; being located. thereon: amcanss of amt l8; on; one side: andz a washer t" betw en; ha hub. member: and. the; ear tit. which, latter is; thereby held: against. a; llar ,ltcn the-strait: Insthisgw y hehub mema him 5 1 is: 11mm the: shaith As in ordinary earin Qfi'thifi hindrthe; gears; l3: and: M; are; per.-

interconnect'ed3. Icy gears. on... a layshaft. imakngwmmannen it is, notzbelieiaeds necesariimstmte; I I shawmmostzciearly bm-Eiaura 4. the -radially Quimrmof thalamus: enlarged at. 2.2!: in. an axial;

3 direction, and the enlarged portion is provided with external splines 22 which slidingly engage with internal splines 23 of a slidable collar 24 constituting the double-acting, slidable, positive clutch element.

The coacting axially-stationary positive clutch elements are respectively a ring of teeth 25, fast with the gear !3, and a ring of teeth 26, fast .with' the gear l4, these toothed rings being internally splined, as shown at 21, and drivingly engaged with corresponding splines on hub portions of the two gears. The hub of each positive clutch element, 25, 25, is formed with a frictional male cone surface with which coacts a corresponding female cone surface on a masking or baulking ring 28, 29. Each baulking ring has external teeth 30 which in certain angular positions of the baulking ring (when synchronism is reached) are aligned with the dog clutch teeth 25 and 26,

respectively. As shown by Figure 3, the axial inner edges of the teeth and of the teeth 25, 26 are bevelled to coact with the ends of the internal splines 23 of the slidable collar 24. 'As shown by Figure 4 particularly, the baulking rings have machined faces 3| to slidably engage with the inner peripheries 32 of the enlarged outer portion 2| of the hub member il, whereby they are slidingly supported by the hub member. In the present instance, each of the baulking" rings 28, 29 is formed with a number of circum' ferentially-spaced lateral arms 33 the ends of which are forked in a radial direction, as shown most clearly by Figure 1, the forked limbsb'ei'ng' aligned with one another to jointly provide an annular groove 34. With this groove coacts an: outwardly-springing ring 35 which has substan{ tially no clearance (in the groove) inan axial direction but which has radial clearance, 'as shown, to enable the ring to be depressed fur ther into the groove. I

The drawings show each baulking ring as having six lateral arms 33 grouped together in pairs. Each pair of arms extend into a slot 36 in the hub member 11, as shown by Figures 1 and 2, with substantial clearance in a circumferential direction, as shown at 3B in Figures 2 and 3, and this enables the baulking rings to move relatively to the hub member to a predetermined extent in a circumferential direction. The baulking rings also have working clearance from the hub'member i! on opposite sides thereof, as indicated at 3?, and, between adjacent pairs of the arms 33, the hub member is peripherally slotted to receive the spring ring 35 with similar working clearanc in an axial direction, as indicated at 38. Internally of the slidable collar 24 are peripheral grooves 4|, '42 and 43 (see Figure 4) adapted in different positions of the collar to coact with the spring ring 35.

The operation of this device is as follows: Figure 4 shows the collar in the neutral position in which the spring ring 35 is engaged with the peripheral groove 4|, and there is clearance at all the male and female cone surfaces. Initial movement of the collar 24 to the right (Fig-' I chronism is reached the drag of the frictional engagement holds the associated masking teeth 30 in the way of the ends of the associated internal splines 23 on the slidable collar. When synchronism is reached the splines of the slidable collar can pass through the masking teeth into engagement with the teeth of the clutch element 25, thereby clutching the gear I3 to the shaft l2 and providing an indirect drive to the shaft l2 through the layshaft above-mentioned. In these conditions the spring ring 35, which has been forced radially inwardly during the final movement of the slidable collar, springs out to the groove 43, whereby to bias the slidable collar to remain in this position.

In a substantially similar manner, movement of the slidable collar 24 from this position fully to the left will first move both baulking rings to the left with a substantial pressure, while the spring ring 35 is being forced out of the groove 43, later to re-engage with the groove 5!. At this time, the baulking ring 28 is quite clear of frictional contact with the clutch element 25, and the baulking ring 29 is frictionally engaged with the clutch element 26, thereby attempting to effect synchronism of the gear !4 and the shaft l2. When synchronism between these two memhers is reached the final movement of the slidable collar 24 to the left can take place until the spring ring 35, after having been again depressed, enters the peripheral groove 42 to maintain the parts in this position (in which the shaft I2 is directly driven) until the collar is again moved.

Such an arrangement ensures that neither vbaulking ring will be frictionally engaged with its associated member except while it is inducing synchronism or when synchronism has been induced and in other conditions there is a complete absence of frictional dragwhich, of course, enables the baulking rings and the associated surfaces to have a long life without material wear taking place. A high thrust can be obtained with a relatively low pressure of the spring l. A synchro mesh change-speed gearing of thekind specified, including a double-acting slidable positive clutch collar, a laterally-rigid outwardlyspringing ring adapted to be engaged with and disengaged from an internal peripheral groove of the collar, baulking rings, and means respectively fast with each of the caulking rings for tying said baulking rings at a number of points to the outwardly-springing ring whereby the latter is always tied to said baulking rings so that there will be substantially no clearance or lostmotion between them in an axial direction, the spring ring serving, on the initial movement of the collar in either direction, for forcing the selected baulking ring at each of the tying points into frictional synchronising engagement and also for positively withdrawing the other baulking ring still further from its coacting element.

synchro-mesh change-speed gearing of the kind specified, including a double-acting slidable positive clutch collar having an internal periph-- -eral groove, a' laterally rigid outwardly-springing ring adapted to be engaged with the groove in certain axial positions of the collar and to be disengaged therefrom in other axial positions thereof, and baulking rings each provided with laterally-extending arms the ends of which are forked in a radial direction to jointly provide in effect an external annular groove to receive the spring-ring with radial clearance and to thus at all times retain it, but to receive it with substantially no clearance in an axial direction,

whereby movement of either baulking ring in the direction for effecting frictional synchronizing engagement positively moves the other baulking ring still further from its coacting element through the intermediary of the said springring.

3. A synchro-mesh change-speed gearing of the kind specified, including a double-acting slidable positive clutch collar having an internal peripheral groove, an outwardly-springing ring adapted to coact with the groove, said collar having internal splines formed therein, an axially-fast hub member of which the radially-outer portion is axially enlarged, external splines formed on said axially-enlarged portion of the hub member slidably coacting with the internal splines of said collar, and baulking rings spaced on opposite sides of said member and slidably supported by the inner peripheries of said axiallyenlarged portion of the hub member, each of said baulking rings being provided with laterally-extending arms and the ends of said arms being forked in a radial direction to jointly provide in efiect an external annular groove to receive the spring-ring with radial clearance but with substantially no clearance in an axial direction, and

6 said hub member being formed to receive said arms with clearance in a circumferential direction, and to receive said spring-rin with clearance both in a radial direction and in an axial direction.

4. A synchro-mesh change-speed gearing, according to claim 3, in which the lateral arms from each of the baulking rings are circumferentially spaced and grouped with those from the other baulking ring in pairs in slots, in the hub member, which provide the said circumferential clearance.

EDGAR DAVID FROST.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,967,065 Rasmussen July 17, 1934 2,101,134 Fawick Dec. 7, 1937 2,260,863 Orr Oct. 28, 1941 2,333,165 Fishburn Nov. 2, 1943 2,364,331 White Dec. 5, 1944 2,369,842 Neracher Feb. 20, 1945 2,369,861 Schotz Feb. 20, 1945 FOREIGN PATENTS Number Country Date 403,319 Great Britain Dec. 21, 1933 OTHER REFERENCES Ser. No. 352,808, Guter et al. (A. P. 0.), pub.

May 18, 1943. 

